[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/echorium_sequence.png]]
A trilogy of [[YoungAdultLiterature young adult]] {{fantasy}} novels by Katherine Roberts, consisting of ''Song Quest'' (1999), ''Crystal Mask'' (2001) and ''Dark Quetzal'' (2003).

The titular Echorium, on the Isle of Echoes, is home to the Singers: people trained in the use of the five [[MagicMusic Songs of Power]]. The trilogy follows the adventures of three successive generations of young Singers and their friends.

----
!!This series provides examples of:
* AccidentalIncantation: The BigBad {{invoke|dTrope}}s this trope by tricking a Singer into [[NotInFrontOfTheParrot using a Song of Power within earshot of a flock]] of semi-sapient BirdPeople that are [[VoiceChangeling perfect vocal mimics]]. Since it's not being consciously directed, the Song doesn't work ''well'', but the BigBad makes do with quantity over quality.
* AllAccessibleMagic: The Songs of Power work for anyone who can sing them. Humans tend to need special training to manage the necessary vocal precision, but in one incident, a flock of BirdPeople [[VoiceChangeling mimic a Song]] perfectly and spread its effects haphazardly.
* AmplifierArtifact: Bluestone and khiz-crystal both amplify the Songs, as well as allowing them to be transmitted over distances.
* AntiMagic: Among other things, khiz can be used to resist the Songs.
* EmptyShell: At its most extreme, the death song Yehn induces a form of living death by "closing doors" in the head.
* GhostMemory: All quetzal have access to the "Memoryplace", the stored experiences of their kind. [[spoiler:Yellow Flowers allow humans to access it too.]]
* MagicMusic: Appears here in the form of the five Songs of Power taught in the Echorium, each used for a specific effect. Certain stones [[AmplifierArtifact can increase their effect]], as can singers working in a group, and for some reason the color blue.
* MindControlDevice: Khiz is used throughout the series to control people and manipulate memories.
* NoOneCouldSurviveThat: The phrase is used almost verbatim in relation to [[spoiler:Frazhin.]] Turns out he did.
* OurCentaursAreDifferent: Intelligent, more or less neutral, and avoidant of humans.
* OurMermaidsAreDifferent: The merlee lean more towards the "obvious sea creature" than "pretty people with legs" end of the scale.
* RaisedByWolves: Shaiala is a human girl raised by a herd of centaurs. She uses their fighting techniques (despite only having half the legs they're designed for), and her inability to [[RiteOfPassage break rocks to get a herdstone]] presents an issue for her.
* RiteOfPassage: To join a herd, young centaurs must travel to a certain canyon and obtain a herdstone. They break them out of the rock by kicking it: a bit of a problem for Shaiala, since she doesn't have hooves.
* SnakePeople: The naga.
* WingedHumanoid: Quetzal are half-bird, half-human. Not only do they have the WingedHumanoid arms-and-wings setup, they have beaks, and are covered in feathers.
----